I fly non-radio probably 90% of the time with no problems what-so-ever. If you are going somwhere phone them first, most will let you in. If you are just pottering around in open FIR, just set your QNH from your known field elevation, keep a good look out and enjoy.
The trouble with radio is that there is no guarentee that the guy your about to crash in to is talking to the same people you are anyway...! just how much use is a flight information service except in ensuring that everyone is on the same RPS... not good if everyone is flying at 1500' VFR.
Kingy